Radiologic Technologist Practice Exam

Which type of detector is identified by the presence of a thin-film transistor array?

1. flat-panel

2. photostimulable phosphor plate (PSP)

3. charge coupled device (CCD)

4. complementary metal-oxide semiconductor (CMOS)

The correct answer is: flat-panel

The identification of a flat-panel detector by the presence of a thin-film transistor (TFT) array is rooted in its design and functionality. Flat-panel detectors, which are widely used in digital radiography, utilize TFT technology to convert X-rays into electrical signals. The TFT array serves as an essential component for reading the data produced by the detector due to its ability to effectively capture and process the signals from each individual pixel. In flat-panel systems, each pixel within the detector is connected to a TFT, which acts as a switch, allowing for the electronic readout of the signal generated when X-rays interact with the detector material. This setup leads to high spatial resolution and efficient data collection, making flat-panel detectors a preferred choice in modern radiographic systems. Other types of detectors, such as photostimulable phosphor plates, charge coupled devices, and complementary metal-oxide semiconductors, do not utilize a TFT array in their construction. Instead, they rely on different mechanisms for capturing and converting X-ray signals into images, which do not feature the same technology as found in flat-panel detectors. This distinction establishes flat-panel detectors as the correct answer when identifying detectors characterized by thin-film transistor arrays.